US regulators are reviewing a proposed agreement between two marine terminal operators at the Port of Miami that would allow the terminals to jointly negotiate terms and conditions with container lines — a first for the United States.

Maersk Line’s acquisition of Hamburg Sud will likely force it to sell its Brazilian flag operation Mercosul Line, which could open the door to CMA CGM or Mediterranean Shipping Co. to enter the closed Brazilian coastal shipping market.

A broad range of US shippers, truckers, and transportation intermediaries are asking federal maritime regulators to consider creating a rule to prevent marine terminals and container lines from charging demurrage and detention fees.